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HARVARD UNIVERSITY 

Library of the 

Museum of 

Comparative Zoology 



OCCASIONAL PAPERS 



APR 1 1989 



of the ^D 

MUSEUM OF NATURAL HISTORl?^^ 
The University of Kansas 
Lawrence, Kansas 

NUMBER 128, PAGES 1-25 MARCH 30,1989 



PHYLOGENETIC RELATIONSHIPS 

OF SEVERAL SUBFOSSIL ANSERIFORMES 

OF NEW ZEALAND 

By 

Bradley C. Livezey' 

Three genera of waterfowl (Anseriformes) are known only from subfossil 
remains from New Zealand (Oliver 1955, Howard 1964): Cnemiornis Owen 
1866, Euryanas Oliver 1930, and Pachyanas Oliver 1955. The first two are 
represented by numerous well-preserved elements, and Cnemiornis is re- 
nowned for its radical morphological modifications related to flightlessness. 
Pachyanas chathamica is represented by relatively few skeletal elements 
(Oliver, 1955) and is not discussed here; the genus currently is under study 
independently by R. J. Scarlett (pers. comm.) and P. R. Millener (pers. 
comm.). With the exception oi Cnemiornis, which has a comparatively long 
history of taxonomic reclassification and description, these subfossil endem- 
ics have received little attention from avian systematists since their original 
description. 

A phylogenetic analysis of Recent anseriform genera (Livezey, 1986), 
based largely on comparative osteology, permitted a reappraisal of the 
relationships and classification of these endemic waterfowl. In this paper I: 
(1) present analyses of characters of Cnemiornis, Euryanas, and the extinct 
New Zealand swan Cygnus sumnerensis; (2) construct phylogenetic trees for 
these groups based on these characters; (3) propose a revised classification of 
these taxa; and (4) discuss selected evolutionary and biogeographic implica- 
tions of these findings. 



'Museum of Natural History, The University of Kansas, Lawrence, Kansas 66045 - 2454 
U.S.A. 



2 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 

MATERIALS AND METHODS 

I examined specimens oiCnemiornis calcitrans and C. gracilis (= septen- 
trionalis) at the British Museum (South Kensington), Canterbury Museum 
(Christchurch), Otago Museum (Dunedin), and the National Museum of New 
Zealand (Wellington). Elements of Cnemiornis illustrated herein were bor- 
rowed from the British Museum (BM). Euryanasfinschi and Cygnus sumner- 
ensis were studied using specimens held at the Otago Museum. I endeavored 
unsuccessfully to borrow specimens oiEuryanas for purposes of illustration 
and confirmation of characters; therefore the analysis of this genus must 
remain preliminary. Skeletal specimensofanhimids,An5eA-ana5',Den^wc}'^na, 
Cereopsis, Branta, and Chenonetta were made available by the Museum of 
Natural History, University of Kansas (KU) and U. S. National Museum of 
Natural History (USNM). 

Fundamentals of phylogenetic (cladistic) analysis are detailed in Wiley 
(1981). Characters of available elements were coded as described in Livezey 
(1986), which in turn was based in large part on the comparative osteology of 
Woolfenden (1961). Anatomical nomenclature follows Howard (1929), 
Woolfenden (1961), and Livezey (1986). Characters are discussed in the 
"phylogenetic order" proposed by Livezey (1986), i.e., from the most 
inclusive (ordinal) characters to the least inclusive characters (those support- 
ing subfamilial and tribal relationships); characters are coded as in Livezey 
(1986). Most skeletal elements of the Recent genera relevant to this study 
were illustrated by Livezey and Martin (1988). Phylogenetic trees were 
generated using the PAUP program (Swofford, 1985) based on the criterion 
of maximal parsimony of character change (Wiley, 1981). 

ACCOUNTS OF GENERA 

Cnemiornis spp. 

Taxonomic history. Owen (1866) described and illustrated a variety of 
postcranial skeletal elements of a previously unknown large, flightless bird, 
which he named Cnemiornis calcitrans, from deposits in a limestone fissure 
atTimaru, South Island. Owen (1866) compared the elements with those of 
the moas (Dinomithidac) and the flightless gruiform Aptornis, but proposed 
no systematic placement for the species. Hector (1873a, b, 1874) examined 
more material for the species, including a skull and a complete sternum, and 
recognized it as a member of the "Lamellirostrate Natatores" (= Anseri- 
formes). Owen (1875, reprinted in 1879) confirmed this classification and, 
based on the additional material collected since his earlier work, concluded 
that the humerus attributed to Cnemiornis in the original description (Owen, 
1866) was actually that of the flightless gmKorm Aptornis. Owen (1875) also 



SUBFOSSIL ANSERIFORMES 3 

presented detailed osteological comparisons of Cnemiomis with the modem 
Cape Barren Goose (Cereopsis novaehollandiae) of Australia and a flightless 
steamer-duck {Tachyeres cf. pteneres) of South America, and, finding that 
Cnemiomis was more similar to the former, inferred that Cnemiornis was of 
anserine affinity. This decision was to influence profoundly the subsequent 
classifications of the genus. 

Forbes (1890) discovered that the coracoids illustrated by Owen (1875, 
1879) as those of Cnemiornis were instead those of the unique flightless 
gruiform Aptornis, and stated that the coracoid of Cnemiornis closely re- 
sembled that of Cereopsis. Forbes (1891) contributed to this perception of 
close relationship with his report ofaCereopsis from New Zealand, to which, 
on the basis of a subfossil cranial fragment, he gave the name novaezealan- 
diae. Lydekker (1891) listed Cnemiornis calcitrans within the Cereopsinae, 
and noted several small specimens that (p. 102) "...indicate a distinct species;" 
he also illustrated a coracoid of Cnemiornis. Forbes (1891, 1892a, b) distin- 
guished a smaller species of Cnemiornis of the North Island (C. gracilis) from 
the larger South Island form (calcitrans); he (1891) also proposed a third 
species, C. minor, on the basis of several tibiotarsi from the South Island. 

Oliver (1930, 1945, 1955) followed Owen in his placement o( Cnemiornis 
with Cereopsis, and he considered both to be "geese." Oliver justified this 
classification using comparisons (mostly cranial) between the two genera, but 
acknowledged a number of conspicuous dissimilariUes in osteology and did 
not discuss comparisons with any other genera. Oliver (1930, 1955) also 
proposed the name C. septentrionalis for the North Island form. Lambrecht 
(1933) listed three species {calcitrans, gracilis, minor) of Cnemiornis, also 
under the subfamily Cereopsinae, after the typical geese. Delacour (1954: 1 99) 
endorsed this practice with the comment: "...the genus Cereopsis has no very 
close living relative, although the exfinct Cnemiornis calcitrans from New 
Zealand was probably similar." 

Dawson (1958) re-evaluated several of the taxonomic decisions based on 
the types designated by Forbes and found that: (1) the supposed Quaternary 
record of Cereopsis "novaezealandiae" from New Zealand was based on the 
misidentification of a fragmentary specimen of Cnemiornis calcitrans, and 
(2) that C. septentrionalis Oliver is a junior synonym of C. gracilis Forbes. 

Both Brodkorb (1964) and Howard (1964) adhered to the tradition of 
lisUng Cnemiornis with Cereopsis but, in accordance with the re-assignment 
of Cereopsis to the shelducks (Tadominae) by Delacour and Mayr (1945), 
placed both genera in or next to this subfam ily. Delacour ( 1 964) dismissed the 
osteologically based conclusion of Woolfenden (1961) and the ethological 
inference of Johnsgard (1961a) that Cereopsis should be returned to the 
Anserinae. 

Character analysis. I examined virtually all major skeletal elements of 
Cnemiornis, including the skull, humerus, radius, ulna, carpometacarpus. 



4 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 

femur, tibiotarsus, tarsometatarsus, sternum, coracoid, scapula, furcula, and 
pelvis. Most were represented by several specimens. The quadrate, pterygoid- 
palatine complex, and trachea were not available for study. The northern and 
southern "species" of Cnemiornis differed in size but were identical in the 
characters discussed below, and are considered together under the generic 
taxon in descriptions and phylogenetic analyses. The skuU and a variety of 
postcranial elements of Cnemiornis were illustrated in Owen (1866, 1875, 
1879) and Hector (1893a, b). 

Cnemiornis shared several derived characters with all others of the 
Anseriformes, including bill lamellae (13b, indicated on the ventral surfaces 
of the premaxillae), recurved and pointed retroarticular processes of the 
mandible (14b), pedicellate basipterygoid processes (20b), and reduced 
furcular process of the furcula (102b). Several synapomorphies support the 
membership oiCnemiornis in the suborder Anseres (anseriforms exclusive of 
the Anhimidae): occipital fontanelles are indicated in outline, although 
(secondarily) closed, as they are in some specimens of large Anserinae (9b, 
see fig. 3 in Hector 1873a); and the caudal terminus of the pubis shows some 
ventral orientation (116b, although more sHght than in Anseranas; Fig. 1). 

Several characters indicate that Cnemiornis represents a branch after 
Anseranas (i.e., appears to be synapomorphic with the Anatidae, sensu 
stricto). One of these is the rounded cranial terminus of the upper bill (12c). 
Another is the lack of an iliac recess in the pelvis (120b, illustrated in plate 
XIV of Hector 1893a). Two others are of questionable reliability because of 
the radical morphological changes associated with flightlessness: the ap- 
proximately equal distal extent of the facets for digits II and III of the 
carpometacarpus (45b) and the absence of a pneumatic foramen in the dorsal 
surface of the coracoid craniad to the sternal facet (93b). The third synapo- 
morphy uniting Cnemiornis with the Anatidae is the absence of a facet for 
metatarsal I on the caudal surface of the tarsometatarsus (71b). 

A number of osteological characters show that Cnemiornis was more 
primitive than Dendrocygna and the rest of the Anatidae, i.e., was symple- 
siomorphic Wiih Anseranas and indicate that Cnemiornis diverged from other 
Anseres prior to the Dendrocygnines. These characters include: the relatively 
caudal orientation of the femoral head (51a); the approximately equal distal 
extent of the tarsometatarsal trochleae for digits II and IV (68a; illustrated in 
Owen, 1866, plate 67, and described by Owen, 1875, pp. 269-270), a 
condition coincident with the lack of caudal rotation of the inner trochlea; a 
moderate lateral displacement of the calcaneum on the tarsometatarsus (72a; 
Fig. 2); the strictly cranio-caudal orientation of the (incompletely ossified) 
distal foramen of the tarsometatarsus (77a; Fig. 3); the presence of a large, 
densely margined foramen at the base of the procoracoid (92a, see below); the 
long, wide, and rounded conformation of the stemocoracoidal process of the 
coracoid (99a, shared also with Cereopsis); and the equal proximal extent of 



SUBFOSSIL ANSERIFORMES 





Fig. 1. Postaceubular portions of the pelvis, lateral surfaces: (A) Anseranas semipalmata 
(KU 80620); (B) Cnemiornis calcitrans (BM 75.12.15.4); (C) Dendrocygna autumnalis (KU 
37725); (D) Cereopsis novae hollandiae (US^fM 430244); and (E) Branta canadensis (KU 
23403). Caudal margins of iUium and ischium (CM) and caudal tenminus of pubis (P) are 
indicated on Anseranas. 



OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 




Fig. 2. Proximal ends of the left tarsometatarsus. caudal surfaces: (A) Anseranas semipal- 
mata (KU 80620); (B) Dendrocygna autumnalis (KU 37725); (C) Cnemiornis calcitrans (BM 
75.12.15.32); (D) Cereopsis novae hollandiae (USNM 429730); and (E) Branta canadensis 
(KU 23403). Calcaneum is shown in stipple. 

the coracoidal process and acromion of the scapula (109a). Also, the costal 
margin of the extremely modified sternum of Cnemiornis occupies slightly 
less than half of the basin length (86a), a primitive proportionality found only 
in anhimids and Anseranas among Recent anseriforms. Cnemiornis lacks, 
however, all of the diagnostic autapomorphies oi Anseranas (Livezey, 1986). 
Three subordinal characters (88, 100, 104) were problematic because of the 
dubious homologies of states related to flightlessness; for example, the 
reduced furcula of Cnemiornis shows moderate flattening of the clavicles, 
reminiscent of that in the Anhimidae (104b), but the state was coded as 
"missing" for Cnemiornis. 

The presence of a conspicuous procoracoidal foramen (92a) in Cnemiornis 
is especially compelling evidence of its primitiveness; this character typically 
occurs among modem Anseriformes only in the Anhimidae and Anseranas 
(Woolfenden, 1961; Livezey, 1986). This primitive character is variable in 
conformational detail, however, and deserves more detailed description. A 
densely margined foramen is characteristic of the anhimids (Chauna and 




Fig. 3. Distal ends of the left tarsometatarsus, cranial surfaces: (A) Anseranas semipalmala 
(KU 80620); (B) Dendrocygna autumnalis (KU 37725); (C) Cnemiornis calcitrans (BM 
75.12.15.32); (D) Cereopsis novaehollandiae (USNM 429738); and (E) Branta canadensis 
(KU 23403). DisUl foramen (DF) and trochlear groove (TG) are indicated; note also the relative 
distal extent of lateral and medial trochleae in A through C vs. that in D and E. 



SUBFOSSIL ANSERIFORMES 7 

Anhima), Anseranas, and Cnemiornis (Fig. 4), although considerable vari- 
ation occurs in at least Chauna (Livezey, 1986). A superficially similar 
structure is found infrequently in Cereopsis (perhaps only in captive birds), 
but is distinguishable (when present) by its thin medial margin, evidently an 
ossified ligament. The "foramina" of most Cereopsis also differ from those 
oi Anseranas and Cnemiornis in lacking an enclosed pneumatic foramen to 
the interior of the element in their caudal margins. Variation of this character 
in Cereopsis is indicated by the range of variation seen in a series of skeletons 
of captive birds held in the U. S. National Museum (Fig. 4). This structure 
varies considerably in Cereopsis, and differences occur even within individu- 
als; the specimen with a completely closed foramen in its right coracoid (Fig. 
4g) lacked the suggestion of closure in its left coracoid (i.e., resembled Fig. 
4e). 

Unfortunately, the early descriptions of the coracoid of Cnemiornis were 
largely erroneous. Owen (1875, 1879) figured coracoids which he attributed 
to Cnemiornis and Cereopsis, but those labelled as Cnemiornis are instead 
those of the ^viiiovmAptornis (Forbes 1 890; pers. obs.), whereas the coracoid 
attributed to Cereopsis also is assigned incorrectly. The latter (plate XXXVII 
in Owen [1875]) is a coracoid with a prominent procoracoidal foramen and 
appears to be identical to the coracoid of Cnemiornis and almost certainly 
pertains to that genus. Lydekker (1891) illustrated a genuine coracoid of 
Cnemiornis, but stated (p. 100) without supporting details that "This speci- 
men (fig. 26) agrees very closely with the coracoid oi Cereopsis."" The notion 
that a procoracoidal foramen occurs in some Anserinae was perpetuated by 
the statement of Howard (1964:250) that "...this foramen is rarely found in the 
Anatidae [sic] except in Anseranas and occasionally in certain swans." 
Although no details were given, this observation by Howard probably 
stemmed from the traditional assignment of certain primitive fossil anseri- 
forms (e.g., Cygnopterus) to the Anserinae (Livezey, 1986) or to the infre- 
quent foramen-like structures seen in procoracoidal processes of some 
anserines (Fig. 4), 

Several synapomorphies unite Cnemiornis with the Anatidae exclusive of 
the Dendrocygninae: the caudal margins of the ilium and ischium present an 
obhquely sloping aspect (114b; Fig. 1); the inner cnemial crest of the 
tibiotarsus shows slight, perhaps equivocal lateral deflection (63b); and the 
tarsometatarsal trochlea for digit II is grooved (74b, Fig. 3; see discussion of 
homoplasy by Livezey and Martin, 1988). 

Numerous characters of the wing and pectoral girdle, elements that were 
modified substantially in association with the loss of flight in Cnemiornis, 
were not comparable to the states defined for Recent anseriforms (Livezey, 
1986). These characters, several of which present difficulties in comparisons 
even among some flighted waterfowl, include features of the carpometacar- 
pus (37, 38,43,44), sternum (78, 79, 81, 88, 89), coracoid (96, 100), furcula 



8 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 




Fig. 4. Cranial portions of the left coracoid, ventral surfaces: (A) Anseranas semipalmata 
(KU 80620); (B) Cnemiornis calcitrans (BM A.1521); (C) Dendrocygna autumnalis (KU 
37725); (D) Branla canadensis (KU 23403); (E-G) Cereopsis novaehollandiae GJSNM 
420244, 429738, 3 1 8044, respectively). Procoracoidal foramen (PF) and pneumatic area under 
brachial tuberosity (BP) are indicated. 

(101, 105), and scapula (108, 112). 

Cnemiornis lacks the diagnostic synapomorphies of the true geese 
(Anserini): it evidently retained the primitive number of 17 cervical verte- 
brae, including the axis and atlas (21a; cf. partial counts in Hector [1873a, b], 
reconstruction in Owen [1875], and mounted skeleton BM 7512154); it 
shows no spur-like elaboration of metacarpal I (42a); there are no pneumatic 
foramina under the brachial tuberosity of the coracoid (95a; Fig. 1); and its 
pubes lack caudal flanges (117a; Fig. 1). Cnemiornis does not share the 
autapomorphic supraorbital process (11a), pneumatic swelHng of the fronto- 



SUBFOSSIL ANSERIFORMES 9 

nasal region (16a), or dorsal bowing of the upper bill (19a) characteristic of 
Cereopsis. 

Neither Brodkorb (1964) nor Howard (1964) offered ostcological support 
for their placement of Cnemiornis with the shelducks (Tadominae); this 
assignment evidently resulted from its traditional association with Cereopsis, 
itself not tadomine (Woolfenden, 1961; Livezey, 1986). However, it seems 
prudent to review the skeletal evidence against a close relationship between 
Cnemiornis and the Tadominae. In addition to the symplesiomorphies of 
Cnemiornis and Anseranas discussed above, several character states of 
Cnemiornis are primitive relative to those of the larger clade including 
Stictonetta, Plectropterus, the Tadominae and the Anatinae: the retention of 
the primitive number of cervical vertebrae (21a); the orientation of the 
humeral capital shaft ridge toward the head (22a); the short capital groove of 
the humems (23a); the unelevated humeral facet of the anterior articular 
ligament (26a); the proximally rotated intemal tuberosity of the humerus 
(27a); the dorsal surface of metacarpal n is flattened proximally (39a); the 
attachment site of M. extensor metacarpi ulnaris on the carpomelacarpus is 
completely proximad to the proximal fomix (43a); and the lack of a medial 
protuberance in the ventral manubrial region of the stemum (79c). In addition, 
Cnemiornis is more primitive than the Tadominae sensu stricto in the 
unenlarged process of metacarpal I (42a) and the tibiotarsus without torsion 
about its long axis (61a). 

Euryanas finschi 

Taxonomic history. Van Beneden (1875) described a small duck from 
subfossil remains found in Eamscleugh Cave, New Zealand, and named it 
Anas finschi. This paper, in French, was followed by a report in English (Van 
Beneden, 1876). In both papers. Van Beneden compared elements oi finschi 
variously with those of the Recent Dendrocygna eytoni. Anas gibberifrons, 
Aythya fuligula, and Bucephala clangula, as well as to the Miocene fossil 
Mionetta (^"Anas") blanchardi (Livezey and Martin, 1988). Hamilton (1892) 
reported the discovery of more specimens oi finschi in the fissures at Castle 
Rocks. 

Oliver (1930) placed the species in its own genus Euryanas, which he 
(1930, 1945, 1955) believed compared favorably (using skull characters) 
with the Maned Duck (Chenonettajubata), a morphologically and behavior- 
ally unique endemic of Austrialia (Delacour, 1959). Lambrecht (1933) placed 
E. finschi within the Anatinae. Howard (1964), following the assignment of 
Chenonetta to the "perching ducks" ("Tribe Cairinini") by Delacour and 
Mayr (1945) and Delacour (1956), placed Euryanas in this tribe. Without 
comment, however, Brodkorb (1964) listed Euryanas within the "spur- 
winged geese" (his Plectropterinae). 



10 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 

Character analysis. I examined specimens of the skull (lacking quadrates 
and pterygoid-palatine complex), humerus, ulna, carpometacarpus, femur, 
tibiotarsus, tarsometatarsus, sternum, costae, coraroid, furcula, scapula, and 
pelvis of Euryanas. S. L. Olson {in litt) described the syringeal bulla of 
Euryanas as being of typical anatine form (sensuAnas, Chenonetta; 6c). The 
skull and a number of the postcranial elements of Euryanas finschi were 
figured by Van Beneden (1875, 1876). 

Inclusion of Euryanas within the suborder Anseres is supported by all 
available characters listed by Livezey (1986), including its typically "duck- 
like" bill. Synapomorphies uniting Euryanas with other Anatidae (sensu 
stricto, excluding Anseranas) are equally numerous , including: the craniome- 
dial orientation of the femoral head (51b), the lateral deflection of the inner 
cnemial crest of the tibiotarsus (63b), the proximal position of the tarsometa- 
tarsal trochlea for digit II (68b), the orientation of the distal foramen of the 
tarsometatarsus (77b), the absence of a procoracoidal foramen (92b) or an 
iliac recess in the pelvis (120b). Two synapomorphies show Euryanas to be 
derived with respect ioDendrocygna — a grooved tarsometatarsal trochlea for 
digit II (74b) and the obliquely sloping caudal margins of the ilium and 
ischium (114b). 

Additional synapomorphies support a closer relationship of Euryanas 
with Stictonetta + Plectropterus + Tadominae + Anatinae than with Thalas- 
sornis or the Anserinae: the orientation of the capital shaft ridge (22b) and 
capital groove (23b) of the humerus; and the presence of a notch (although 
weak) in the external rim of the carpal trochlea (38b), the rounded dorsum of 
metacarpal II (39b), and the position of the scar of M. extensor metacarpi 
ulnaris (43b) of the carpometacarpus. With the exception of a widening of the 
scapular blade (108b), Euryanas lacks the synapomorphies characteristic of 
the Anserinae (e.g., characters 85a, 95a; Livezey, 1986). 

Compared with the shelducks, Euryanas is primitive in the unelevated 
facet for the anterior articular ligament (26a) and proximally oriented internal 
tuberosity (27a) of the humerus, and lacks the tadomine synapomorphies of 
a carpometacarpal spur (42a) and tibiotarsal torsion (61a). Euryanas is 
plesiomorphic with respect to the Anatinae in a number of characters, notably 
in the rounded, anconally concave deltoid crest (25a) and prominent, but- 
tressed external tuberosity (32a) of its humerus. 

These characters indicate that Euryanas diverged from modern anatid 
lineages after the basal anatid grade of Dendrocygna, Thalassornis, and the 
Anserinae, but before the Tadominae (Livezey, 1986). Euryanas lacks the 
somewhat convergent features indicative of diving specialization found in 
Thalassornis, pochards (Aythyini), sea ducks (Mergini), and stiff-tailed 
ducks (Oxyurini), especially characters of the femur (52a, 54a, 55a, 56a), 
tibiotarsus (64a, 65a), tarsometatarsus (69a, 75a), sternum (78a), and pelvis 
(119a). 



SUB FOSSIL ANSERIFORMES 1 1 

Both Euryanas and Stictonetta have long, peg-like ventral manubrial 
spines (79d), a character shared also by the more derived genus Anas; this 
feature, however, is variable and its transformational pattern is inadequately 
resolved (Livezey, \9S6). Euryanas differs from Stictonetta in two characters 
of the coracoid, both of problematic polarity and transformation: the ventral 
surface is without a deep depression (96b) and the ventral sternal facet is 
without a buttress (100a). 

The presence of an asymmetrically enlarged, unfenestrated syringeal bulla 
in Euryanas (6a; S. L. Olson, in litt.) supports, however, a closer relationship 
between Euryanas and the terminal clade of Plectropterus + Tadorninae + 
Anatinae than with Stictonetta. 

Cygnus sumnerensis 

Taxonomic history. Forbes (1890a, b) and Sclater (1890) announced the 
discovery of three coracoids and a partial humerus of a large, extinct swan 
from a cave near Christchurch, which Forbes (1890a) named Chenopis 
sumnerensis. Forbes (1891) reported the collection of more material for the 
species, and speculated that more than one species might be represented. 
Forbes (1893a, b) later reported numerous specimens of the swan from the 
Chatham Islands. 

Oliver (1930) and Lambrecht (1933) listed Chenopis sumnerensis as a 
typical swan. Oliver (1955) later reassigned the fossil swan to Cygnus in 
accordance with current generic taxonomy; he also proposed a new species 
name, C. chathamicus, arguing that the earlier name should be abandoned 
because the types for the species described by Forbes ( 1 890a, b) could not be 
identified. Dawson (1958) reported the rediscovery of this type material and 
relegated chathamicus to junior synonomy of C. sumnerensis, a restoration 
followed by Brodkorb (1964) and Howard (1964). 

Character analysis. I examined all important skeletal elements of C. 
sumnerensis except the quadrate, pterygoid-palatine complex, and syrinx. 
Oliver (1955:603) figured a mounted, presumably composite skeleton of this 
species. 

C. sumnerensis is synapomorphic with modem geese and swans (Anseri- 
nae) in the presence of foramina on the midline and cranial margin of the 
dorsal surface of the sternal basin (89a), the presence of foramina under the 
brachial tuberosity of the coracoid (95b-c), the lack of a ventral depression 
on the coracoid (96b) , reduced coracoidal tuberosities on the furcula (101 a-b), 
and a caudal widening of the pubis (1 17b). The species is united with extant 
swans (Cygnini) by the caudomedial extension of the xiphial region of the 
sternal basin (85b), the presence of a small foramen in the cranial edge of its 
uninflated sternal carina (87b), and ±e comparatively medial orientation of 
the sternal intermuscular line (88a). Two apparent synapomorphies are shared 



12 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 

with the modem geese (Anserini): an enlarged process of metacarpal 1 (42c) 
and the diverse foramina present under the brachial tuberosity of the coracoid 
(95c). The moderately low consistency and sexual variation of the first 
(Livezey, 1986), the intermediate condition of the second, and the hmited 
material available for characterization of C. sumnerensis support the interpre- 
tation that these similarities are convergent. C. sumnerensis lacks the derived, 
trachea-related modifications of the sternal carina and furcula found in Olor 
(87c, 106b). 

CONSTRUCTION OF TREES 

Methodological Considerations 

For derivation of phylogenetic trees, I used the characters described in 
Livezey (1986), but excluded from analyses those characters which were not 
informative for inferences concerning relationships among subfamilies. 
Excluded characters were unique autapomorphies (particularly of Anhimidae, 
Anseranas, and Plectropterus), diwing-rthted autapomorphies oiThalassor- 
nis (several convergent with some members of the Tadominae and Anatinae), 
and characters which were invariant among the Anseriformes exclusive of the 
Tadominae and Anatinae. This reduced the characters analyzed to 62 which 
were useful for inferences in the basal segment of the order (Figs, 2 and part 
of Fig. 3 in Livezey, 1986), the segment which, on the basis of the foregoing 
character analyses, included the subfossil genera to be placed. As in Livezey 
(1986), several characters were analyzed as unordered (Table 1). In all 
analyses, two primary weighting schemes were employed: the "standard" 
weighting scheme of Livezey (1986), in which the syringeal bulla (character 
6) was given a weight of two and all other characters were given unit weight; 
and the "unit" weighting scheme in which all characters were given unit 
weight. 

A further simplification was made through the reduction of the taxonomic 
units considered in construction of trees. Recent taxa analyzed were reduced 
to 12 taxonomic units, in addition to the hypothetical ancestor proposed by 
Livezey (1986): the Anhimidae, seven single-genus lineages {Anseranas, 
Cereopsis, Coscoroba, Dendrocygna, Thalassornis, Stictonetta, and Plec- 
tropterus), and four taxa representing well-established monophyletic groups 
of genera {Branta-Anser, Cygnus-Olor, Tadominae, and Anatinae). This 
streamlined set of Recent taxa was used for separate (14-taxon, 62-character) 
phylogenetic analyses of Cnemiornis and Euryanas using the exhaustive 
branch-and-bound algorithm in the PAUP program, a time-consumptive 
technique for finding all possible shortest trees which is practical only with 
small numbersof taxa (Swofford, 1985). The body of evidence confirming the 
systematic position of Cygnus sumnerensis among the moderately derived 



SUBFOSSIL ANSERIFORMES 



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14 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 



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SUBFOSSIL ANSERIFORMES 15 

members of the modem genus Cygnus rendered unnecessary a numerical 
analysis of the species; a species-level analysis of Cygnus is not possible at 
present. 

Cnemiornis spp. 

The phylogenetic relationships of this genus were analyzed under a variety 
of alternative character codings and weights. An initial analysis was based on 
all 62 characters, for which 41 were determined for Cnemiornis (Table 1); all 
other character states were coded as "missing." A series of subsequent, 
progressively "conservative" analyses were performed in which an additional 
1-7 characters considered to be problematic for Cnemiornis — two of the 
carpometacarpus (38, 43), one of the sternum (79), one of thecoracoid (100), 
two of the furcula (104, 105), and one of the pelvis (118) were coded as 
"missing" as well. Both the "standard" and "unit" weighting schemes were 
employed. In addition, each of these analyses was performed with another 
somewhat problematic character, the procoracoidal foramen (92), assigned a 
unit weight Gike all other characters) or with weight zero (i.e., it did not affect 
the derivation of trees); the latter treatment seems justified in light of 
intrageneric variation in this character and the possibility that the foramen 
typical of Cnemiornis is homologous to those found infrequently in Cereopsis 
(Fig. 4). None of these analytical variants altered the position of Cnemiornis 
in the resultant trees or the number of equally short trees found, but these 
modifications of data did produce minor differences in tree lengths and 
consistency indices. ConsequenUy, the trees depicted in Fig. 5 are based on 
the most conservative analysis of Cnemiornis, in which 34 character states 
were specified for the genus. 

In all analyses, Cnemiornis was inferred to be a lineage which diverged 
after Anseranas but before the divergence of the Recent taxa included in the 
Anatidae by Livezey (1986); i.e., Cnemiornis was found to be the sister-group 
of the suborder Anseres exclusive of Anseranas (Fig. 5). The position of 
Cnemiornis was supported by 15 character changes, between Anseranas and 
Cnemiornis, and seven character changes supportive of monophyly of the 
other Anseres. Two characters which were retained in all analyses and which 
were derived in Cnemiornis but primitive in Dendrocygna (characters 74, 
114) were inferred to be reversals in the latter. 

An unexpected finding of the branch-and-bound analyses of the reduced 
data set for extant taxa was that several, equally parsimonious permutations 
oi Dendrocygna, Thalassornis, and Ihe Anserinae are possible (Fig. 6). Only 
one of these is most parsimonious if Cnemiornis is included in the analysis 
(Fig. 5); this arrangement, in which the Anserinae are inferred to be the sister- 
group to the rest of the (Recent) Anatidae, differs from both of the two 
topologies described by Livezey (1986). 



16 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 



Ancestor 



Anhimidae 



Anseranas 



LENGTH = 106 
CI = 0.76 



Den droc ygna 
— Thalassornis 

St ictonetta 

Plec tropterus 
Tadorninoe 
Ana 1 1 nae 



-d 



-c 



C oscoroba 



K 



Cygnus + Olor 
Br onto + Anser 
Cereopsis 



CNEMIORNIS 







Cygnus + Olor 








Cygnus + Olor 








c 










Coscoroba 

Sranta + Anser 






' — Cereopsis 








• Branta -'r Anser 









Fig. 5. Phylogenetic trees for Cnemiornis and basal lineages of Anserifonmes: (A) Complete 
tree with one of three equally parsimonious tqjologies (for branches overlaid with stipple) for 
the geese (Cereopsis, Anser, and Branta); (B, C) Alternative tq)ologies for the geese. 

There also were three equally parsimonious topologies within the Anseri- 
nae, alternatives which were possible whether Cnemiornis was included in 
the analysis or not (Fig. 5). These topological variants are not directly relevant 
to the position of Cnemiornis in the tree, but one of these topologies — in 
which Cereopsis is hypothesized to be the sister-group to the rest of the 
subfamily (Fig. 5b) — would be favored in the event that symplesiomorphies 
between Cnemiornis and Cereopsis (not shared by other anserines) were to be 
documented. A strict consensus tree for the analysis of Cnemiornis depicts the 
Anserinae as a trichotomy involving Cereopsis, Branta + Anser, and the 
Cygnini. 

Euryanas finschi 

Of the 62 characters employed in the analyses of subfossil taxa, 50 were 
determined [or Euryanas (Table 1); the other 12 were coded as "missing." An 
exhaustive search for all most-parsimonious trees using the "standard" 
weighting scheme found nine equally parsimonious topologies, but in each 
Euryanas was the sister-group to the clade Tadominae -i- Anatinae (Fig. 7a). 



SUBFOSSIL ANSERIFORMES 



17 



Ancestor 



A nhimidae 

— An ser anas 



LENGTH = 106 
CI = 0.76 



Dendrocygna 
• Anser I noe 



— Dendrocygna 

T halassornis 




T holossornis 



other Anatidoe 



■ Coscoroba 
• Cygnus ■*- Olor 
— C ereopsis 



' Branta -t- Anser 

St I ctonett a 
Pleclropterus 

CTadorn I nae 
Anoti nae 



' Anserinoe 



Anser i n oe 

Dendrocygna 

- T halassornis 



other Anotidae 



Fig. 6. Phylogenetic trees for extant basal lineages of Anseriformes: (A) Complete tree with 
oneof three equally parsimonious topologies (for branches overlaid with stipple) ior Dendrocygna, 
Thalassornis, and Anserinae (the last taxon shows three topologies depicted in Fig. 5); (B-C) 
Alternative topologies for the grade including Dendrocygna, Thalassornis, and Anserinae. 

The topological variants resulted from two previously discussed, unresolved 
segments: (a) three alternative positions oWendrocygnus, Thalassornis, and 
Anserinae; and (b) the three arrangements of Cereopsis, Branta + Anser, and 
the Cygnini within the Anserinae. Using the "unit" weighting scheme, 12 
equally parsimonious trees were found, but once again Euryanas was the 
sister-group to the clade composed of Tadominae and Anatinae in each. The 
majority of the topological variants resulted from combinations of arrange- 
ments within the unresolved grade and geese (discussed above); reduced 
weight of the syringeal bulla, however, permitted an additional sequence for 
the grade composed of Sdctonetta and Pleclropterus (three of 12 trees; Fig. 
7b). 

PROPOSED CLASSIFICATION 



Based on the trees discussed above, I conclude that: 

(1) Cnemiornis is the sister-group to the Anatidae (sensu Livezey, 1986). 

(2) Inclusion of Cnemiornis in the phylogenetic analysis indicated that the 
subfamily Anserinae (true geese and swans, including Cereopsis) may be the 
sister-group to the rest of the family Anatidae (including Dendrocygninae). 

(3) Euryanas appears to be a moderately derived "proto-duck," a member 
of a lineage that arose after the Anserinae, Dendrocygninae, and Thalassor- 
nithinae but before the divergence of the Tadorninae from the Anatinae; it 
appears to be the sister-group to the clade composed of the Tadominae and 
Anatinae. 



18 



OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 



Ancestor 



Anhim idae 

— Anser a nas 



B 



(— Plectropterus 

Stictonetta 

Tad or ni nae 
Anat i nae 
EURYANAS 




LENGTH =110 
CI = 0.74 



Dendrocygna 
I — T halassornis 



Anserinae 



I — St ic tonetta 

Plectropterus 

Tadorninae 
Anati nae 
' — EURYANAS 




Fig. 7. Phylogenetic trees for Euryanas and basal lineages of Anserifonmes: (A) Complete 
tree using weighting scheme of Livezey (1986), unresolved grade overlaid in stipple; (B) 
Alternative topology for terminal clade involving Euryanas if syringeal buUa (character 6) is 
given unit weight. 

(4) Cygnus sumnerensis is a true swan (Cygnini), more derived than 
Coscoroba but less so than Olor; it agrees in its characters with those of the 
possibly paraphyletic genus Cygnus {sensu stricto; Livezey, 1986), which 
includes C. atratus of Australia. 

Accordingly, I propose the following classification, based on the relevant 
section of the schemes presented by Livezey (1986) and Livezey and Martin 
(1988), and annotational conventions of Wiley (1981). Taxa analyzed herein 
are shown in boldface. Sedis mutabilis indicates that the phylogenetic 
sequences of associated sections are unresolved. 

Order Anseriformes 
Suborder Anseres 

Family Anseranatidae 
Family Cnemiornithidae Stejneger, 1885 
Genus Cnemiornis Owen, 1865 
C. calcitrans Owen, 1865 
C. gracilis Forbes, 1891 
Family Anatidae 

Subfamily Dendrocygninae^ 
Subfamily Dendrocheninae^ 
Subfamily Thalassomithinae' 
Subfamily Anserinae^ 

Tribe Anserini (possibly paraphyletic) 
Tribe Cygnini 



^sedis mutabilis 



SUBFOSSIL ANSERIFORMES 19 

Genus Coscoroba 

Genus Cygnus (possibly paraphyletic) 
C. sumnerensis (Forbes, 1890) 

Genus Olor 
Subfamily Stictonettinae 

Genus Stictonetta 
Subfamily Plectropterinae 
Subfamily Euryanatinae, subfam. nov. 

Genus Euryanas Oliver, 1930 

E.finschi (Van Beneden, 1875) 
Subfamily Tadominae 
Subfamily Anatinae 

Diagnoses for Cnemiomithidae and Euryanatinae are as for the included 
genera (see character analyses above). The Cnemiomithidae can be charac- 
terized additionally by large size and reduced pectoral elements, both of 
which were illustrated and described previously (Owen, 1866, 1875; Hector, 
1873a, b; Howard, 1964); representative measurements were given by 
Howard (1964). Note that in the foregoing partial classification the subfamily 
name Thalassomithinae is used instead of the incorrectly derived taxon 
Thalassominae given in Livezey (1986). 

DISCUSSION 

This reappraisal indicates that Cnemiornis and Euryanas represent two 
variably primitive lineages endemic to New Zealand. The earlier classifica- 
tions of these taxa were based largely on comparisons that were influenced 
profoundly by biogeographic preconceptions; classifications oi Cnemiornis, 
Euryanas, and Cygnus sumnerensis were based largely on comparisons with 
Cereopsis, Chenonetta, and Cygnus atratus of Australia, respectively. This 
was a strangely parochial approach to the study of waterfowl, an ancient 
group in which several modern genera have cosmopolitan distributions (e.g., 
Cygnus, Tadorna, Anas). The early systematic analyses of these endemics 
also were limited by the taxa compared (e.g., Owen, 1875) and the virtual 
exclusion of postcranial characters from the pioneering work of Oliver (1930, 
1945, 1955). The failure of previous workers to distinguish between primitive 
and derived characters undoubtedly contributed to these classificatory prob- 
lems, as has been the case for many paleomithological investigations (Crac- 
raft, 1980). The methodological and philosophical justification for cladistic 
analysis in paleontological study was reviewed by Schoch (1986). 

The early perception of an "alliance" between Cnemiornis and Cereopsis 
evidently was based on very limited phenetic comparisons and the compara- 
tively large body size of both genera. Cnemiornis was extremely derived 



20 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 

osteologically and of immense size (by anseriform standards); both charac- 
teristics were related to its obvious flightlessness, and reductions of wing 
elements and the sternal carina in this genus are among the most extreme in 
the Anseriformes (Livezey, in prep.). However, in virtually all other charac- 
ters the genus is very primitive. The unique skeletal characters of Cnemiornis 
led Oliver (1945) to conclude the genus deserved subfamilial rank, while 
paradoxically maintaining the view that Cnemiornis "is a close ally of 
Cereopsis" (p. 125). The traditional view of such an "alliance" was so 
profound that, following the re-classification of Cereopsis to the Tadominae 
(largely on behavioral grounds) by Delacour and Mayr (1945), Cnemiornis 
was similarly reclassified by Howard ( 1 964) and Brodkorb (1964). Ironically, 
Howard (1964) herself had warned against such taxonomic revisions (in the 
context of the classification of a fossil anserine), indicating (pp. 268-269) 
"...the need for caution in attempting to trace an evolutionary line based on the 
names of fossils without careful review of the characteristics of the fossils 
themselves in the light of accumulating knowledge of existing forms." 

Wetmore (1943) described the fragmentary tibiotarsus of a goose from 
Hawaii, Geochen rhuax, which he felt resembled Cereopsis (and by associa- 
tion of traditional taxonomy, Cnemiornis) most closely. As with Cnemiornis, 
Geochen followed the later movement of Cereopsis to the shelducks in both 
Brodkorb (1964) and Howard (1964). In contrast, the present study indicates 
that: (1) Cnemiornis is not a goose and is not closely related to Cereopsis (a 
true goose, Anserini) but instead represents a very early branch of the 
Anseriformes (i.e., is the sister-group to the Anatidae, sensu stricto); and (2) 
neither Cnemiornis nor Cereopsis belongs in the shelducks (Tadominae). The 
finding that Cereopsis is anserine and not tadomine in relationship was 
inferred by several earlier investigations of osteology (Shufeldt, 1913; 
Verheyen, 1953; Woolfenden, 1961; Livezey, 1986). Furthermore, prelimi- 
nary examinations of Geochen and flightless Thambetochen of Hawaii 
(Olson and Wetmore, 1976; Olson and James, 1982) indicate that these genera 
are probably anserine and not tadomine in relationship. 

It has been suggested to me that several of the "primitive," non-gooselike 
characters found in Cnemiornis (especially of the pelvic limb) may be 
reversals associated with the terrestrial specialization, a condition related in 
tum to the evident flightlessness of the genus. Unfortunately, no compelhng 
evidence for such functional relationships or for the occurence of such 
reversals in other anseriforms has been demonstrated. Lacking such support, 
and given that several other "terrestrial" waterfowl (e.g., Thambetochen, 
Branta sandvicensis, Chloephaga) show none of these putative reversals (cf. 
Miller, 1937), the parsimonious inference remains that these characters 
reflect an early divergence for Cnemiornis. "Adaptive" rationalizations to 
retain Cnemiornis in the Anserini, and in particular to suggest that Cnemiornis 
is the sister-group of Cereopsis, not only assume synapomorphies not in 



SUBFOSSIL ANSERIFORMES 21 

evidence, but also imply additional homoplasy in the associated phylogenetic 
hypothesis and are based on unsupported ad hoc arguments concerning 
presumed evolutionary change. A similar suite of "adaptational" rationaliza- 
tions was suggested by Davies and Frith (1964) to conserve the classification 
of Anseranas within the Anserinae in the face of growing morphological 
evidence of its extreme primitiveness(cf.Delacoiir, 1954;Johnsgard, 1961b; 
Woolfenden, 1961). 

Based on my studies of the osteology of waterfowl and the limited 
comparisons involving Cnemiornis, I suggest that the following structures 
may prove useful for further testing of the systematic position of the genus: 
the conformational details of the palate; patterns of cranial canals, including 
the morphology of foramina in the cranioventral floor of the cranium; the fine 
structure of vertebrae, especially the cervical vertebrae and those composing 
the synsacrum; and anatomical details of the calcaneum of the tarsometatar- 
sus. Furthermore, I predict that the determination of homologous states and 
transformation series of such fine-grained characters may prove problematic 
if attempted for the entire order Anseriformes; study of a more restricted 
subgroup of taxa (e.g., Anseranas, Cnemiornis, Dendrocygna, Cereopsis, 
Anser, and Stictonetta) probably would be adequate for inferences regarding 
Cnemiornis. At least one of these character complexes — the morphology of 
the vertebral column — would provide insights into the augmentation of 
cervical vertebrae in Anseranas and the Anserinae and thereby also shed hght 
on the relationships within the Anserinae. 

Euryanasfinschi also deserves continued study. The unfortunately limited 
material available for this study notwithstanding, there is substantial evidence 
that Euryanas is not anatine or tadomine {sensu Livezey, 1986); this lends 
some support to the observation by Oliver (1 945: 1 24) thatEMryano.y "...seem[s] 
to be more primitive than the typical ducks." However, I am not persuaded by 
Oliver (1945) that Chenonetta and the New Zealand teal {Anas chlorous and 
A. aucklandica) are similarly plesiomorphic, although Chenonetta is osteol- 
ogically unusual in several respects (Woolfenden, 1961; Livezey, 1986). 
Skeletal elements deserving of particular attention in Euryanas are the skull, 
carpometacarpus, and tibiotarsus; the (modal) number of cervical vertebrae 
would be particularly useful for phylogenetic inference. Worthy (1988) 
inferred that there has been modest shortening of wing elements in Euryanas 
during recent millenia; whether this trend has modified any of the osteological 
characters considered here is not known. Two humeral characters which I 
found to be problematic in Euryanas (characters 22 and 33) seem likely can- 
didates for such evolutionarily modified features; the capital shaft ridge (22) 
also may be similarly modified in Chenonetta, which shows a reversal in this 
character (Livezey, 1986). 

Inclusion of Cnemiornis in the analysis indicated that, of the three 
alternative sequences of the extant taxa Dendrocygna, Thalassornis, and 



22 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY 

Anserinae (Fig. 6), placement of the Anserinae as the sister-group of the rest 
of the Anatidae is most parsimonious (Fig. 5). The relatively poor resolution 
of the phylogenetic sequence of the Anserinae and Thalassominae was 
indicated previously by Livezey (1986) and also by an analysis of the 
Miocene fossil Mionetta blanchardi (Livezey and Martin, 1988). The impor- 
tance of fossils in the (cladistic) inference of phylogenetic relationships of 
extant taxa was demonstrated by Panchen and Smithson (1987) and Gauthier 
et al . ( 1 988). In practice, however, this advantage must be weighed against the 
disadvantages associated with incomplete data, worn material, uncertain 
association, and unknown sex of many specimens of fossil and subfossil taxa. 

The phylogenetic hypotheses proposed here add to the growing evidence 
of the diversity and probable origin of the Anseriformes in the Southern 
Hemisphere (Livezey, 1986). The very early divergence of Cnemiornis is 
concordant with the numerous flightlessness-related autapomorphies in the 
genus, in that it provides a much greater period of time for the accumulation 
of these evolutionary novelties. A parallel example of morphologically 
radical flightlessness in an ancient carinate lineage is the gruiform Aptomis 
(also endemic to New Zealand); formeriy thought to be a rail (Oliver, 1945), 
Aptornis instead probably represents a separate family related to the Rallidae 
(cf. Olson, 1975). 

The finding ihdXEuryanas is nota member of the Anatinae underscores the 
diversity of the more primitive "proto-ducks" in the Southern Hemisphere in 
the past. Moreover, Euryanas, the extant Thalassornis of Africa and Sticton- 
etta of Australia (Livezey, 1986), and several Miocene forms from the 
Northern Hemisphere (Livezey and Martin, 1988) indicate that there was a 
more widespread radiation of these "duck-Uke" anseriforms in the late 
Tertiary. 

ACKNOWLEDGEMENTS 

This study was supported by National Science Foundation (USA) grant 
BSR-85 16623. I am grateful for the arrangements and kind hospitality 
afforded me by: J. Darby, Otago Museum; G. Tunnicliffe, Canterbury 
Museum; J. A. Bartle and N. H. S. Hyde, National Museum of New Zealand; 
B. Gill, Auckland Museum; curatorial staffs of the U. S. National Museum 
and the Museum of Natural History, University of Kansas; and C. Walker, 
British Museum (Natural History). P. S. Humphrey, D. Siegel-Causey, and 
two anonymous reviewers commented on the manuscript, and S. L. Olson 
provided useful criticisms of an earlier version of this paper; K. Corbin and 
M. Schmalz typed its several drafts. 



SUBFOSSIL ANSERIFORMES 23 

SUMMARY 

The phylogenetic relationships of several endemic subfossilAnseriformes 
of New Zealand — Cnemiornisspp.,Euryanasfinschi,andCygnussumneren- 
sis — are re-examined using the osteological characters analysed in an earlier 
study of anseriform systematics (Livezey, 1986). Flightless Cnemiornis, 
traditionally considered to be a "goose" and closely related to the extant 
Australian genus Cereopsis, is shown to be a very primitive anseriform 
representing a branch shortly after that ofAnseranas of Australia. Euryanas 
finschi is found to be a moderately derived "proto-duck," most probably 
representing the sister-group to the clade including Tadominae and Anatinae. 
Cygnus sumnerensis is confirmed to be a true swan (Cygnini), more derived 
than Coscoroba but less so than /or. A revised classification is presented and 
selected biogcographic, analytical, and evolutionary implications are dis- 
cussed. 

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